X-ray film sequences

ABSTRACT

A changer for sequentially exposing a plurality of film cassettes during patient X-ray procedures. A sequencer permits either automatic or semiautomatic operation of the changer. Means are further provided for selective vertical positioning of the changer with respect to an X-ray machine. Radiation detection means are optionally provided for controlling the sequencer.

[4 1 Oct mite States Patent X-RAY FILM SEQUENCES 3,624,398 ll/l971250/66 FOREIGN PATENTS OR APPLICATIONS Primary Examiner-James W.Lawrence Assistant Examiner-B. C. Anderson [22] Filed:

AttorneyFryer, Tjensvold, Feix, Phillips & Lempio [57] ABSTRACT Achanger for sequentially exposing a plurality of film [51] Int. Cl.

[58] Field of Search......................

25 5 cassettes during patient X-ray procedures. A sequencer permitseither automatic or semiautomatic operation of [56] References Cited thechanger. Means are further provided for selective vertical positioningof the changer with respect to an X-ray machine. Radiation detectionmeans are optionally provided for controlling the sequencer.

18 Claims, 9 Drawing Figures m m m m m m m m A n m m H mma ne Or. SWCB DWmam 999 NHHH UZSm 602 464 909 344 23 PATENTED 21975 3.763.370

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HOWARD A HANSON BY 2 z 5;; 7 wr ATTORNEYS PMENTED 21975 3.763.370

sum 2 or 3 346 I 4 PM! 326 I INVENTOR.

HOWARD A. HANSON BYj Z Wf ATTORNEY PATENTEDBCT 2197s sum 3 [IF 3INVENTOR.

HOWARD A, HANSON fimfiat ATTO NEYS X-RAY FILM SEQUENCES BACKGROUND OFTHE INVENTION This invention is directed generally to a film cassettechanger for use in X-ray applications. More particularly, this inventionconcerns an Xray table for use in X-ray applications, primarily,translumbar aortography and femoral arteriography, which table hasincorporated there in an automatic, film cassette changer.

Currently, serialographs are an especially valuable tool in the field ofmedical diagnosis. Serialographs broadly involve the taking of aplurality of X-rays at desired intervals in a sequential manner.

By injecting a suitable contrast dye into the patients blood stream, aseries of X-ray photographs may be taken at predetermined intervals tothereby ascertain various patient conditions. For example, as noted inU.S. Pat. No. 2,999,159 to Curry, it is a conventional technique infemoral arteriography to take a series of X-ray photographs of apatients legs in order to diagnose various conditions by following theprogress of a dye or tracer element in the leg arteries. Constrictionsof the artery such as caused by arteriosclerosis which impede flow ofblood may be readily discerned by a radiologist. Important informationcan be obtained from these photographs as to both the location andextent of such condition which materially assists in the performance oflater surgical operative procedures.

The prior art devices have not proven entirely satisfactory for manyreasons. For instance, these prior art devices tend to be rather largeand difficult to handle. This materially contributes to cost in view ofthe additional time and effort that must be expended by the operator inmanaging such devices.

Critical to the achieving of medically useful, diagonostic X-rays inthis area are precision in positioning and control of the sequentialmovement of the film cassettes. Also of extreme benefit is thecapability of optionally having either automatic or semiautomaticsequencer operation.

Another problem with the prior art is the complexity and consequent highcost of the devices. Complexity in number and arrangement of parts hasresulted in prior art machines being both costly to buy and maintain.A-n associated problem is the difficulty of loading and un loading filmcassettes from these devices.

. SUMMARY OF THE INVENTION As a solution to these and other problems,there is herein prpvided a device for sequentially moving a plurality offilm cassettes with respect to an X-ray beam. The device comprises acarriage which is latched into position with respect to the X-ray beampath and means biasing said carriage in a first direction' with respectto the beam path. A sequencer provides the option of automatic orsemiautomatic releasing of the latching means whereby the carriage meansis actuated so as to sequentially movea plurality of film cassettes withrespect to the direction of travel of the biasing means. Verticalpositioning means are further provided for selective verticalpositioning of the changer with respect to an X-ray machine. Radiationdetection means are optionally provided for controlling the sequencer inresponse to X-ray machine operation.

OBJECTS OF THE INVENTION I It is, therefore, an object of this inventionto provide a film cassette changer which enables the sequential movementof a plurality of film cassettes with respect to an X-ray beam path.

It is a further object of this invention to provide the film cassettechanger for X-ray use having a sequencer for controlling the filmchanger operation.

It is a further object of this invention to provide a radiation sensormeans for controlling sequencer operation.

It is a further object of this invention to provide a film cassettechanger having vertical positioning means so as to enable precisepositioning of the changer with respect to an X-ray machine.

It is a further object of this invention to provide an X-ray filmcassette changer having a verticallypositionable table for supporting apatient for diagnostic X-ray procedures.

It is another object of this invention to provide an X-ray apparatus forsequentially changing a plurality of film cassettes wherein a pluralityof the cassettes are oriented in stacked relation under the patient andbeneath the beam path such that sequential removalof cassettes from thebeam path enables sequential exposure of the plurality of cassettes.

It is a still further object of this invention to provide an apparatusfor changing film cassettes in X-ray applications wherein the motivatingmeans for changing is spring potential energy.

It is a further object of this invention to provide an X-ray filmcassette changer device which is both easy to load and unload as well asoperate.

Other objects and advantages of the present invention will becomeapparent from the following description and claims and as illustrated inthe accompanying drawings which, by way of illustration only, showpreferred embodiments of the present invention and the principles ofoperation thereof. It is to be understood that the scope of theinvention is not to be limited thereto, but is to be determined by thescope of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric, top'quarterview, partially broken away, of an X-ray table embodying the filmcassette changer of the instant invention;

FIG. 2 is a top plan view of the same with top panels removed so as toshow the internal working mechanism of the device;

FIG. 3 is a view of the same in vertical elevation with the front panelremoved;

FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 3illustrating a portion of vertical positioning mechanism;

FIG. 5 is a vertical cross-sectional view taken along line 5-5 in FIG. 3illustrating with particularity the tray return mechanism;

FIG. 6 is an enlarged, partial view of the doubleroller supportmechanism;

FIG. 7 is an overall circuit diagram of the sequencer;

FIG. 8 is a circuit diagram of an auxiliary radiation sensor control,override circuit; and

FIG. 9 is a circuit diagram of the vertical positioning means for thetable.

DETAILED DESCRIPTION Referring to the drawings, there is shown generallyat in FIG. 1 an X-ray table adapted for patient support which comprisesthe instant invention. The table itself comprises a bottom enclosure 12and a film cassette changer module 14. The cassette changer module maybe detached from the bottom enclosure in a conventional manner forfacilitating moving or when it is desired to use the module alone. Inthis latter instance, the module would typically be placed on anyconvenient static support such as a table. The following discussion willfirst focus on the film cassette changer and associated apparatus afterwhich a discussion of the vertical positioning mechanism will beattempted.

FILM CASSETTE CHANGER MECHANISM Film cassette changer module 14comprises generally a rectangularly-shaped, box-like structure which isslightly over twice the width and once the length of a standard X-rayfilm cassette, i.e. 14 inches by 36 inches.

As best seen in FIG. 5, the film cassette changer module is adapted tohold four cassettes numbered 1 4' as shown in phantom line. Filmcassettes l 3' are contained in movable trays 1-3, respectively. It maybe further noted that cassette 4' has no corresponding tray. Rather,this bottommost film cassette reposes on the bottom interior wall 16 ofmodule 14. When in this position and with trays 1-3 containing cassettesl 3', respectively, located thereover, the changer is in its cocked oroperative condition as will be hereinafter described.

Returning again to FIG. 1, the module further comprises a pair ofhorizontally-directed top panels 18, 20 which serve to both enclose theinternal mechanism of the changer module as well as to provide patientsupport. The changer module 14 including left top panel 18 may be madeof any convenient material, including those pervious to X-rays, i.e.,wood, metal, plastic, etc. The right top panel, on the other hand, whichis located directly over the stack of film trays 1-3 in their cockedposition, must be made of an X-ray pervious material. Means are alsoprovided immediately under the right top panel to accommodate twostandard 14 inch by 17 inch X-ray grid panels used in eliminatingsecondary scattered radiation emanating from the patient, therebyconsiderably enhancing the resultant X-ray photographs.

The trays or cassette carriage means 1-3 are conveniently, generallyrectangularly-shaped structures adapted to encompass a singleconventional X-ray film cassette. These trays may be fashioned, forexample, by forming lightweight metal angles, e.g., aluminum ormagnesium, into a generally rectangularly-shaped tray such as shownat 1. This tray is comprised of a pair of spaced, parallel, longitudinalmembers 22 joined by a pair of spaced, parallel, lateral members, one ofwhich is shown at 24. Completing the box-like appearance of the tray isa rectangularly-shaped plate of lead or other X-ray impervious material26, the purpose of which will be hereinafter described.

Longitudinally positioned adjacent to the back interior wall 28 of themodule is a plurality of springs comprising spring-biasing means 30, 32,and 34. As best seen in FIG. 2, a typical spring 30 is fixedly attachedas at 1 and 36 to the side interior wall 38 by any conventional means.The other end of the spring 40 is secured to a first pulley 42 byconventional means. Completing the connection with the typical tray 1 isa cable 44 which may be made of metal, wire or rope having a first endof which is fixed to a vertical shaft 48 spaced from and fixed to wall28 and a second end 50 fastened by conventional means to the back rail22 of tray 1.

As best seen in FIG. 1, vertical shaft 48 is fixed at each end to wall28 by means of a pair of pillow blocks 52 or the like. After passingthrough pulley 42, cable 44 is passed around a pulley 54 rotativelymounted on vertical shaft 48. By appropriately setting the springconstant of spring 30 as well as its length in relation to the length ofa cable 44 and the lateral distance to be travelled by the trays, thesesprings provide a potential energy source or means for imparting motionto the trays.

As best seen in FIG. 2, travel in the lateral or arrow direction is madepossible by use ofa plurality of rollers travelling in guide rails orchannels. More particularly, a pair of roller assemblies 56 is mountedon each lateral assembly 24 of representative tray 1. These rollerassemblies are accommodatingly fitted for travel in the lateraldirection in a pair of guide rails 58 mounted on the side interior wallsof module 14.

As shown in FIG. 6, each roller assembly 56 comprises alaterally-extending, horizontal shaft 60 to which is fixed forrotational movement a vertical roller or wheel 62. A bracket means 64which is fixed with respect to shaft 60 serves to mount the horizontalroller or wheel 66. Shaft 60 is fixedly attached at its remaining end 68to lateral member 24 by conventional means such as bolting or riveting.Wheel 66 is rotatively supported by pivot means 70. Wheels 62 and 66bear against the interior walls of guard rail 58 at points 72 and 74,respectively. This provides support in two directions and facilitatesmovement of the trays.

Returning again to FIG. 5, the mechanism for cocking the trays in theiroperative position will be described. The initial position of tray 1 isshown in phantom at 1". This position is achieved by means ofspringbiasing means 30 pulling the subject tray into abuttingrelationship against a plurality of bumpers 76 (one of which is shown)which are mounted in a vertical orientation on the back wall 28 ofmodule 14 so as to cushion the trays impact. These bumpers may be madeof any convenient, resilient material such as rubber.

In this position, a pull rod means 78 having an end portion 80 curvedaround the lattermost-oriented roller assembly rod of tray 1 (not shown)and the other end of which is capped by a pull knob 82, has said knob inabutting relationship with front panel 84 of module 14. By manuallypulling knob 82 away from the front of panel 84 to the position shown at82', the tray may be pulled by means of hook 80 on the end of rod 78 tothe position shown at 1. In this position rod 78 is at position 78'. Itmay be noted that this movement is against the biasing force of spring30 as transmitted to cable 44, as best seen in FIG. 2.

As also seen in this figure and in FIG. 1, the tray may then be latchedinto this operative position by means of solenoid-operated latchmechanisms 86, 88, corresponding with trays 1, 2, and 3, respectively.Extending from representative solenoid 86 is a plunger 92. In itsunretracted condition, the plunger extends into the path of one of theroller assemblies, as shown in FIG. 2, so as to prevent movement in thedirection of the biasing force. Alternatively, a projection could beprovided on the tray for this latching purpose. The plunger 92 would beactuateable by means of solenoid 86 out of its'impeding position shown,whereupon the tray would move in the arrow direction shown until itreached the abutting relationship with the bumper 76 as shown at I" inFIG. 5.

The operation of the film cassette changer module will now be described.Later on in this disclosure, the operation of the sequencer whichcontrols the operation of the film cassette changer through themechanism of the solenoids will be described in detail. Before theserialographs are taken, the changer module is as shown in FIG. 1. Themodule is then loaded with an unexposed film cassette in each of thethree trays 1-3 as well as a fourth cassette 4' being placed on thebottom floor of the module, as best seen in FIG. 3. Knobs 82, 96, and 98may be sequentially, manually actuated in order to pull the trays l, 2,and 3, respectively, slightly out of the module 14 through the generallyrectangularly-shaped opening 100. The fourth cassette 4' may be merelyinserted through opening 100 to its operative position.

Alternatively, front longitudinal member 22 could be hinged so as topermit insertion of a cassette without the necessity of pulling tray 1from the module 14. Trays 2 and 3 would be similarly provided with hingemeans.

A patient would then be placed on the patient support table with hishead in the region of top panel 102 and, if femoral arteriography is tobe performed, one of his legs and pelvic regions supported on right toppanel 20. The table would then be positioned under an X-ray machine (notshown) such that the X-ray beam would pass through the patient and thenthrough X-raypermeable or -transmissible right top panel 20.

The sequencer (not shown), once activated, would control the X-raymachine to emit a beam of proper strength and duration for exposing thetopmost film cassette 1' contained in tray 1. It may be recalled thatthe bottom of the trays, e.g., 26 of tray 1, is X-ray impermeableinasmuch as it is made of lead or the like. Thus, the remainingcassettes are shielded from exposing radiation at this point. Uponcompletion of the exposure, the sequencer would activate solenoid 86, asshown in FIG. 2, to withdraw plunger 92 and thereby unlatch the tray.The tray would move in the direction shown in the figure under theinfluence of biasing spring 30 until it abutted the plurality of bumpers76 as shown by 1" in FIG. 5.

The sequencer would then repeat this cycle by causing serial exposure ofremaining cassettes 2' 4. The remaining two solenoids 88, 90 wouldactuate, in turn, to enable withdrawal of trays 2 and 3 from theoperative position under the X-ray beam to the inoperative positionagainst bumper 76. It may be parenthetically noted that top panel 18 maybe made of an X-ray impermeable material i.e., lead, in the event thatX-ray scatter proved to be a problem. It may further be noted that sinceeach tray is provided with an X-ray impermeable bottom, the remainingcassettes located thereunder in the operative position will not beexposed until the tray directly thereover has been removed. It may bestill further noted that position lights 104, 106, and 108, are lightedsequentially by means hereinafter to be described as trays 1, 2, and 3,respectively, reach their inoperative position against bumpers 76.

posed cassettes could then be removed by reversing the procedure used inloading. This would complete a serialograph cycle.

It may be parenthetically noted at this juncture that an alternativeembodiment would include a radiation sensor located in the path of thebeam. The radiation sensor or detector and associated circuitry (notshown) would override the operation of the sequencer so as to ensuredelaying actuation of the subsequent tray in the series until after theX-ray exposure has been completed. The necessary circuitry will alsohereinafter be described.

SEQUENCER CIRCUIT With particular reference to FIG. 7, there is showngenerally the sequencer citcuit 112 in association with a cam mechanism114 which forms a part of the sequencer. The following discussion willdescribe the circuit by means of tracing the operation first of thesequencer in the manual mode wherein tray sequencing is controlled bythe operator. Secondly, the actuation of the circuit will be describedin the automatic mode where automatic tray sequencing is accomplished bymeans of time-delay circuitry.

It should be noted at the outset that the X-ray machine 116 may be anyconventional X-ray unit as is common in the art. The power supply is aconventional 1l0-volt source 118. One of the lines 120 from this sourceis conventionally grounded. The remaining two hot lines 122, 124 havelocated therein fuses 126 for obvious reasons.

For both the manual and automatic modes, the closing of main powerswitch 128 energizes main power pilot light 130. It may beparenthetically noted that all of the circuit elements, i.e., switches,etc., are shown in their normal positions. That is to say, switchesshown in their open position on the circuit are normally open, andswitches shown in their closed position are normally closed.

At the same time that the main power switch 126 is closed, cam-operatingmotor 132 is energized. Motor 132 is a conventional brake solenoid motorwith capacitor 134 associated therewith. Energizing brake solenoid 135causes power shaft 136 to rotate. Conversely, de-energizing the clutchsolenoid causes the motor to be braked. Power shaft 136 has mountedthereon a plurality of cams 138, 140, 142, and 144 which operatesswitches 146, 148, 150, 152, respectively. Manual closing of push-buttonoperating switch 154 completes a circuit across relay 156. This causesrelay contact 1560 i to close and thereby energize brake solenoid 135whereupon power shaft 136 begins to rotate. Camactuated switch 152 isclosed by the rotation of cam 144 by means of the switch leaving adetent position on the cam.

At the same time that relay 156 is energized, relay contact 156a isclosed which latches the relay in the energized position throughnow-closed, cam-actuated switch 152. Switch 152 will remain closed untilcam 144 reaches another detent position as will be hereinafterdescribed.

Also at the same time that relay 156 is energized, relay contact l56bcloses causing the initiation of operation of X-ray machine 116.Normally, the timing of the X-ray would be set internally in the X-raymachine and would be completed prior to activation of solenoid 86controlling the tray 1 actuation. This is accomplished by setting adetent position on cam 138 which is associated with cam-operated switch146 at a point on said cam sufficiently removed that the X-ray durationdesired could occur. As the shaft continues to rotate, cam 138 rotatesto this predetermined detent which causes switch 146 to close.

Closing of switch 146 accomplishes several functions. First of all,pilot light 160 is energized and solenoid 86 which latches the topmosttray (not shown) is also energized. Push-button, position-marker switch162 in the path of tray 1 (not shown) is closed by the tray reaching itsfull limit of travel. This causes pilot light 104 to be energized. Afteractuation of solenoid 86, power shaft 136 continues to rotate untilanother detent in cam 144 is reached and switch 152 is again opened.Opening of switch 152 causes relay 156 to be de-energized which, inturn, opens relay contacts 156a,

156b, and l56c. Opening of relay contact 1560 de-energizes brakesolenoid 135 and power shaft 136 stops rotating.

A new cycle is commenced by again manually depressing operatingpush-button switch 154 which results in the closing of cam-operatedswitch 148 by cam 140 and the lighting of pilot light 166 and theenergizing of solenoid 168 controlling tray 2 (not shown). At thecompletion of its travel, this tray actuates pushbutton, position-markerswitch 170 which lights pilot light 106.

A third actuation of operating switch 154 will initiate yet anothercycle which results in the closing of camoperated switch 150 by cam 142and the lighting of pilot light 172 and the energizing of solenoid 174so as to release tray 3 (not shown). Again, the push-button markerswitch 176 is closed by tray 3 completing its travel, and pilot light108 is energized. Since the fourth cassette is stationary, the onlyoccurrence as the cams continue to rotate is that another X-rayphotograph is initiated by the closing of contact 156b, and the camsreturn to their reset position in preparation for another serialograph.At this point, shaft 136 and its cams will have made a completedrevolution and switch 152 will be at the initial detent position. Theautomatic mode of operation will now be described.

In the automatic mode, the initial steps for manual operation, i.e.,main power switch 128, pilot light 130, and motor 132, are followed inthat order. Automatic sequence switch 178 having pilot light 180associated therewith is manually closed. This both energizes the pilotlight as well as places three time-delay relays 182, 184, 186 on line.These relays may be manually set to provide varying time delays betweentray actuation by means of a slide wire or other rheostat means 188,190, 192, respectively, as is conventionally known in the art. Ofcourse, these would normally be preset before commencement of aserialograph sequence. The length of time required would, of course,depend on the duration of X-ray as well as the time required to remove atray from the operative position. This can normally be found byexperimentation.

As with the manual mode of operation previously discussed, the automaticmode is initiated by depressing and releasing push-button switch 154.This again causes the energizing of relay 156. As with the manual mode,relay contact 156a closes and latches the relay into the energizedposition. In addition, contact 156b also closes to actuate X-ray machine116. Simultaneously, contact 1560 closes and energizes clutch solenoid135. Thus, motor 132 drives shaft 136 which rotates the cams includingcam 138 to a detent position so as to close switch 146. Closing of thisswitch energizes pilot light 160 and the first tray solenoid 86. Thefirst tray reaches its limit of travel and closes pushbutton markerswitch 162 to light pilot light 104.

At the same time that switch 146 closes, time-delay relay 182 is alsoenergized. After a time interval preset by rheostat means 188, relaycontact 182a closes. This contact is in parallel with now-open,pushbutton switch 154. Thus, relay 156 is again energized so as to beginanother cycle. The cycle is repeated until the third tray is released bysolenoid 174. A fourth and last X-ray photograph is taken and the camsreturn to the reset position, as more fully described above with themanual mode. It may be noted that the circuitry also includes a relay194 having contacts 194a and 194b. This relay closes when main powerswitch 128 is closed so as to power for the circuitry for a table liftmechanism to be hereinafter described by way of terminals 123, 125. Itmay be further noted that the circuitry contains switches 195, 197, and199, which are individually, manually actuable so as to permit each ofthe trays to be relatched in their operative position.

Also included in the circuit is relay 196 having contacts 196b with boththe manual and semiautomatic modes. This relay is energized bycam-operated switch 152 returning to its normal position and beforecontact 156a opens. The purpose of this relay is to momentarily open theX-ray machine timer circuit in order that it may reset itself for asubsequent exposure.

RADIATION DETECTOR CIRCUIT As an alternative embodiment, the circuitshown in FIG. 7 can be amplified by the addition of the radiationdetector or sensor circuit shown in FIG. 8. Circuit elements havinganalogous correspondence in the first embodiment are marked with primes.

As shown in the figure, detector has one side grounded and the otherside connected to one input of operational amplifier 200 throughresistor 202. The other input of amplifier 200 is grounded through aresistor 204. A feedback loop is comprised of capacitor 206 and resistor208 connected in parallel across the first input and output of theamplifier.

The output of amplifier 200 is connected through resistor 210 to a firstinput of a second amplifier 212. The second input of amplifier 212 isconnected through resistor 214 to a slide wire potentiometer 216 whichhas one end connected to a D.C. power source at 218 and the other endgrounded.

The output of amplifier 212 is connected to the base of transistor 220through resistor 222. The emitter is grounded while the collector isconnected to a conventional D.C. power source by means of a seriesresistor 226 and a parallel connection of diode 228 and a relay 230.The'function of the diode is to protect the relay from currenttransients during power loss.

The operation of this circuit is as follows. Since relay contact 230a islocated in the circuit between brake solenoid and power lines 122' and124', the operation of the brake solenoid and consequently the cammechanism of the sequencer can be overridden by the radiation detectorcircuit. Thus, if an X-ray is in progress, radiation sensed by detector110 will cause a current to energize relay 230 to open contact 2300 andthereby prevent tray actuation by the cams. Completion of the X-rayresults in a loss of radiation to detector I10 and relay 230 will bede-energized to once again close contacts 2300. The sensor or detector110 may be conveniently a conventional silicon solar cell. Actuation isaccomplished by means of radiation striking fluorscent material of thecell which causes it to emit light rays to be picked up by a solar cell.

Adjustment of sensitivity is accomplished by means of slide wirepotentiometer 216. Moving the slide wire toward ground would tend toincrease sensitivity, while moving it away from'ground would tend todecrease sensitivity.

TABLE LIFT MECHANISM Turning again to FIG. 2, there is shown a tablelift mechanism which comprises an endless chain 300 driven over aplurality of sprockets 302 by means of a motor 304. The motor is aconventional reversible, electric motor having a belt drive sprocket 308linked to the shaft sprocket 310 by means of a belt 312.

As best seen in FIG. 4, sprocket 310 is fixedly mounted to avertically-oriented shaft 314 which is, in turn, rotatively supported bya pair of pillow blocks 316. At one extremity of shaft 314 is mounted achain for drive sprocket 318 for driving chain 300 in either direction.

The bottom enclosure 12 basically comprises an upper frame portion 320containing most of the upper working mechanism and a lower frame portion322 which supports the former by means of a plurality of wheels orcastors 324.

At each corner of the lower frame portion is an extension or projectionof 326 which may be conveniently an angle to which is welded orotherwise fixed a threaded bolt means 328, as best seen in FIG. 4.Passing through each bolt means is a threaded shaft 330 which threadablyengages the threaded bolt means as best seen in FIGS. 3 and 5. The freeend of each threaded shaft is rotatively mounted in a pillow block 332.Rotation of shaft 330 causes the upper frame portion to be raised orlowered in respect to the lower frame portion.

CIRCUITRY FOR LIFT TABLE MECHANISM Returning to FIG. 9, there is shownan electrical circuit for operating the table lift mechanism. Motor 304is suitably connected to a switch 334 contained on the face of enclosure12, as shown in FIG. 1. This switch is comprised of switches 336' and338 for upward and downward motion, respectively. Also included aremotor relays 340 and 342 controlling the relay contacts 340a and 3420,respectively. Also included are upward and downward limit switches 344and 346, respectively. As best seen in FIG. 3, these limit switches maybe physically installed on the internal wall of the enclosure 12 so asto be the path of projection 326 and thereby limit the travel of thelift table.

It is understood that the foregoing description is merely illustrativeof preferred embodiments of the invention; and the scope of theinvention is not to be limited thereto, but is to be determined by thescope of the appended claims.

What is claimed is:

1. A device for sequentially moving a plurality of X-ray film cassetteswith respect to the path of an X-ray beam, comprising:

a housing having means for moving X-ray film cassettes in a firstdirection with respect to the beam path, wherein said means for movingX-ray film cassettes comprises tray means for containing X-ray filmcassettes, guide means for guiding said tray means in said firstdirection,

and means biasing said tray means in said first direction wherebyrelease of said latching means causes said tray means to move in saidfirst direction, and

wherein the improvement comprises a sequencer means for controlling saidmeans for moving said cassettes in a predetermined sequential order,wherein said sequencer means comprises:

a source of power,

a motor means operable by said power source,

a cam mechanism including cam means driven by shaft means,

means intermediate said shaft means and said motor means for selectivelycoupling said shaft means to said motor means,

switch means actuable by said cam means for actuating said latchingmeans, and

operating switch means for controlling the means intermediate said shaftmeans and said motor means whereby rotation of said cam meansaccomplishes sequential actuation of said tray means through saidlatching means.

2. The invention of claim 1 wherein said guide means comprises guiderails and wherein said tray means comprises trays adapted to receiveX-ray film cassettes and roller means on said trays operativelyassociated with said guide rails whereby said trays may be motivated inthe direction of said guide rails.

3. The invention of claim 2 wherein the trays and associated guide railsare arranged in stacked, spaced relation in the X-ray beam path in theiroperative position for making exposures and said first direction istransverse to the beam path whereby sequential removal of trays allowsexposure of a series of X-ray film cassettes.

4. The invention of claim 3 wherein said trays comprise bottom portionsof X-ray impermeable material whereby exposure of the next higher trayin the stack of trays will not expose the tray directly below said nexthigher tray.

5. The invention of claim 4 further including provision in said housingfor supporting an X-ray film cassette directly below said stack of traysin their operative position.

6. The invention of claim I wherein said means biasing said tray meanscomprises spring means.

7. The invention of claim 1 further including bumper means in the pathof movement of said tray means for cushioning impact of said tray means.

8. The invention of claim 1 further including means for returning saidtray means to its operative position against the force of said biasingmeans.

9. The invention of claim 1 wherein said sequencer means furthercomprises manual operating means whereby said means for moving saidcassettes is manually controlled by an operator as well as,

automatic operating means whereby said means for moving said cassettesis automatically controlled without the intervention of an operator.

10. The invention of claim 1 further including time delay means forcontrolling said latching means whereby automatic sequencing of saidtray means is accomplished.

11. The invention of claim 1 further including position marker meansassociated with said tray means for indicating when said tray means hasreached its limit of travel subsequent to sequencing.

12. The invention of claim 1 wherein said sequencer means furthercomprises means for controlling the operation of an X-ray machine so asto integrate X-ray exposure to sequencing of the tray means.

13. The invention of claim 1 wherein said latching means comprisesolenoids and further including switch means for actuating saidsolenoids so as to reset said tray means in the operative position.

14. The invention of claim 1 further including radiation-detectorcircuitry circuitry having a radiation detector means positioned so asto be in the X-ray beam path for overriding the operation of saidsequencer means so that sequencing of a tray means will be preventeduntil after the X-ray exposure has been completed.

15. The invention of claim 14 wherein said radiation detector circuitrymeans further comprises means for adjusting the sensitivity of saidradiation detector means.

16. The invention of claim 1 further including a support meanssupporting said housing and vertical positioning means operativelyassociated with said support means for selectively raising and loweringsaid support means and thereby said housing.

17. The invention of claim 16 wherein said support means comprises anupper enclosure supporting said housing and a lower enclosure positionedtherebelow, and wherein said vertical positioning means comprises:

a power source,

reversible motor means operable by said power source, manually-operablecontrol circuit means for selectively communicating power to operatesaid motor means in either the forward or reverse directions,

and

means interconnecting said upper and lower enclosures operable by saidmotor means to vertically position said upper with respect to said lowerenclosure.

18. The invention of claim 17 wherein said control circuit means furthercomprises limit switch means for limiting the vertical movement of saidupper support means with respect to said lower support means.

UNITED STATES PATENT OFFICE CERTIFICATE 0F CQRECHON Patent No 376-337ODated 10/2/73 Inventofls) HOWARD A. HANSON It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

In the title, change "X-RAY FILM SEQUENCES" to --X-RAY FILM SEQUENCER-Column 11, line 24, change "circuitry circuitry" to --circuitry means-.

Signed and sealed this 26th day of March 1974.

I (SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents FORM PO-1050 (10-69)

1. A device for sequentially moving a plurality of X-ray film cassetteswith respect to the path of an X-ray beam, comprising: a housing havingmeans for moving X-ray film cassettes in a first direction with respectto the beam path, wherein said means for moving X-ray film cassettescomprises tray means for containing X-ray film cassettes, guide meansfor guiding said tray means in said first direction, and means biasingsaid tray means in said first direction whereby release of said latchingmeans caUses said tray means to move in said first direction, andwherein the improvement comprises a sequencer means for controlling saidmeans for moving said cassettes in a predetermined sequential order,wherein said sequencer means comprises: a source of power, a motor meansoperable by said power source, a cam mechanism including cam meansdriven by shaft means, means intermediate said shaft means and saidmotor means for selectively coupling said shaft means to said motormeans, switch means actuable by said cam means for actuating saidlatching means, and operating switch means for controlling the meansintermediate said shaft means and said motor means whereby rotation ofsaid cam means accomplishes sequential actuation of said tray meansthrough said latching means.
 2. The invention of claim 1 wherein saidguide means comprises guide rails and wherein said tray means comprisestrays adapted to receive X-ray film cassettes and roller means on saidtrays operatively associated with said guide rails whereby said traysmay be motivated in the direction of said guide rails.
 3. The inventionof claim 2 wherein the trays and associated guide rails are arranged instacked, spaced relation in the X-ray beam path in their operativeposition for making exposures and said first direction is transverse tothe beam path whereby sequential removal of trays allows exposure of aseries of X-ray film cassettes.
 4. The invention of claim 3 wherein saidtrays comprise bottom portions of X-ray impermeable material wherebyexposure of the next higher tray in the stack of trays will not exposethe tray directly below said next higher tray.
 5. The invention of claim4 further including provision in said housing for supporting an X-rayfilm cassette directly below said stack of trays in their operativeposition.
 6. The invention of claim 1 wherein said means biasing saidtray means comprises spring means.
 7. The invention of claim 1 furtherincluding bumper means in the path of movement of said tray means forcushioning impact of said tray means.
 8. The invention of claim 1further including means for returning said tray means to its operativeposition against the force of said biasing means.
 9. The invention ofclaim 1 wherein said sequencer means further comprises manual operatingmeans whereby said means for moving said cassettes is manuallycontrolled by an operator as well as, automatic operating means wherebysaid means for moving said cassettes is automatically controlled withoutthe intervention of an operator.
 10. The invention of claim 1 furtherincluding time delay means for controlling said latching means wherebyautomatic sequencing of said tray means is accomplished.
 11. Theinvention of claim 1 further including position marker means associatedwith said tray means for indicating when said tray means has reached itslimit of travel subsequent to sequencing.
 12. The invention of claim 1wherein said sequencer means further comprises means for controlling theoperation of an X-ray machine so as to integrate X-ray exposure tosequencing of the tray means.
 13. The invention of claim 1 wherein saidlatching means comprise solenoids and further including switch means foractuating said solenoids so as to reset said tray means in the operativeposition.
 14. The invention of claim 1 further includingradiation-detector circuitry circuitry having a radiation detector meanspositioned so as to be in the X-ray beam path for overriding theoperation of said sequencer means so that sequencing of a tray meanswill be prevented until after the X-ray exposure has been completed. 15.The invention of claim 14 wherein said radiation detector circuitrymeans further comprises means for adjusting the sensitivity of saidradiation detector means.
 16. The invention of claim 1 further includinga support means supporting said housing and vertical positioning meansoperatively associated with said suPport means for selectively raisingand lowering said support means and thereby said housing.
 17. Theinvention of claim 16 wherein said support means comprises an upperenclosure supporting said housing and a lower enclosure positionedtherebelow, and wherein said vertical positioning means comprises: apower source, reversible motor means operable by said power source,manually-operable control circuit means for selectively communicatingpower to operate said motor means in either the forward or reversedirections, and means interconnecting said upper and lower enclosuresoperable by said motor means to vertically position said upper withrespect to said lower enclosure.
 18. The invention of claim 17 whereinsaid control circuit means further comprises limit switch means forlimiting the vertical movement of said upper support means with respectto said lower support means.